Oracle教程 2023-03-24

Oracle 视图 DBA_HIST_FILESTATXS 官方解释，作用，如何使用详细说明

本站中文解释

Oracle视图DBA_HIST_FILESTATXS是基于AWR收集的统计信息，使用它可以跟踪在特定时间范围内数据文件的使用情况，它会显示磁盘I/O活动以及文件访问类型。

主要用途：

1. 查看表空间和数据文件的文件I/O的使用情况，以及如果调整缓存参数对I/O负载的影响。

2. 识别哪些数据文件出现了偏斜的I/O负载，并作出行动来改善该现状，比如创建多个数据文件，或者添加额外的表空间，来改善负载不均衡的问题。

3. 通过识别更新型的Busy Buffer中的文件，来解决一些对少数数据文件的过度访问的问题。

使用方法：

1. 首先启动相应的监控，这可以通过AWR报告或者DBMS_WORKLOAD_REPOSITORY.START_SNAPSHOT来完成。

2. 然后执行查询：SELECT * FROM DBA_HIST_FILESTATXS;

3. 最后结束监控，也可以使用AWR报告或者DBMS_WORKLOAD_REPOSITORY.STOP_SNAPSHOT完成。

官方英文解释

DBA_HIST_FILESTATXS displays information about file read/write statistics.

This view contains snapshots of V$FILESTAT.

Column	Datatype	NULL	Description
`SNAP_ID`	`NUMBER`	`NOT NULL`	Unique snapshot ID
`DBID`	`NUMBER`	`NOT NULL`	Database ID for the snapshot
`INSTANCE_NUMBER`	`NUMBER`	`NOT NULL`	Instance number for the snapshot
`FILE#`	`NUMBER`	`NOT NULL`	File identification number
`CREATION_CHANGE#`	`NUMBER`	`NOT NULL`	Change number at which the data file was created
`FILENAME`	`VARCHAR2(513)`	`NOT NULL`	Name of the data file
`TS#`	`NUMBER`	`NOT NULL`	Tablespace number
`TSNAME`	`VARCHAR2(30)`		Name of the tablespace
`BLOCK_SIZE`	`NUMBER`		Block size of the data file
`PHYRDS`	`NUMBER`		Number of physical reads done
`PHYWRTS`	`NUMBER`		Number of times DBWR is required to write
`SINGLEBLKRDS`	`NUMBER`		Number of single block reads
`READTIM`	`NUMBER`		Time (in hundredths of a second) spent doing reads if the `TIMED_STATISTICS` parameter is `true`; `0` if `TIMED_STATISTICS` is `false`
`WRITETIM`	`NUMBER`		Time (in hundredths of a second) spent doing writes if the `TIMED_STATISTICS` parameter is `true`; `0` if `TIMED_STATISTICS` is `false`
`SINGLEBLKRDTIM`	`NUMBER`		Cumulative single block read time (in hundredths of a second)
`PHYBLKRD`	`NUMBER`		Number of physical blocks read
`PHYBLKWRT`	`NUMBER`		Number of blocks written to disk, which may be the same as `PHYWRTS` if all writes are single blocks
`WAIT_COUNT`	`NUMBER`		Shows the number of waits at the file level for contended buffers. This value includes the individual wait events that are included in the buffer busy waits wait event. See Also: “buffer busy waits”
`TIME`	`NUMBER`		Time spent waiting for the wait events in the `WAIT_COUNT` column
`OPTIMIZED_PHYBLKRD`	`NUMBER`		Number of physical reads from Database Smart Flash Cache blocks
`CON_DBID`	`NUMBER`		The database ID of the PDB for the sampled session
`CON_ID`	`NUMBER`		The ID of the container that `CON_DBID` identifies. Possible values include: `0`: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs. `1`: This value is used for rows containing data that pertain to only the root n: Where n is the applicable container ID for the rows containing data

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